Weight bearing elements are common components in many constructions. For example, floor and ceiling joists function as weight bearing elements and are frequently found in residential and commercial buildings. Although there is a large variety of weight bearing elements, many weight bearing elements are limited in length and weight bearing capacity due to the material(s) from which they are constructed, and are oftentimes difficult to incorporate into constructions because of their structure or cost.
Weight bearing elements can be grouped in two classes, elements predominantly made from wood, and elements predominantly made from metal. Generally, weight bearing elements made from wood are found in older constructions, and were traditionally made from solid saw lumber. However, due in part to a sharp decline in the supply of appropriate solid saw lumber, alternative weight bearing members which use less solid saw lumber were developed. Such alternatives generally comprise two chords (a top, compression chord/member and a bottom, tension chord/member extending the length of the weight bearing element) coupled together by a web (see U.S. Pat. No. 5,664,393 issued on Sep. 9, 1997 to Veilleux et al., U.S. Pat. No. 5,560,177 issued on Oct. 1, 1996 to Brightwell, and U.S. Pat. No. 4,228,631 issued on Oct. 21, 1980 to Geffe). A commonly found alternative is an I-joist having sawn lumber chords or plywood chords. Such an alternative element advantageously reduces the amount of wood required for construction and thereby reduces the weight of the weight bearing element. However, almost all forms of wooden weight bearing elements are relatively heavy when compared to equivalent metal structures. Moreover, wooden weight bearing elements are oftentimes limited to lengths of about less than 24'.
Generally, weight bearing elements made from metal are lighter than comparable wooden elements, may span longer distances and are fireproof. Furthermore, such elements are often available in continuous lengths. Weight bearing elements made from metal are common in various forms, including light gauge steel C-profile joists, trichord open web joists and screw fabricated steel truss joists (see U.S. Pat. No. 5,687,538 issued on Nov. 18, 1997 to Frobosilo et al., U.S. Pat. No. 5,499,480 issued on Mar. 19, 1996 to Bass, U.S. Pat. No. 5,457,927 issued on Oct. 17, 1995 to Pellock et al., U.S. Pat. No. 5,157,883 issued on Oct. 27, 1992 to Meyer, U.S. Pat. No. 4,793,113 issued on Dec. 27, 1988 to Bodnar, U.S. Pat. No. 4,729,201 issued on Mar. 8, 1988 to Laurus et al., U.S. Pat. No. 4,159,604 issued on Jul. 3, 1979 to Burrell, U.S. Pat. No. 3,686,819 issued on Aug. 29, 1972 to Atkinson, U.S. Pat. No. 3,541,749 issued on Nov. 24, 1970 to Troutner, U.S. Pat. No. 3,221,467 issued on Dec. 7, 1965 to Henkels, U.S. Pat. No. 2,578,465 issued on Dec. 11, 1951 to Davis, Jr. et al., U.S. Pat. No. 2,387,432 issued on Oct. 23, 1945 to Laney, and U.S. Pat. No. 157,994 issued on Apr. 4, 1950 to Palmer).
Light gauge steel C-profile joists may be manufactured from roll-formed galvanized steel. However, in order to achieve appropriate rigidity, light gauge steel C-profile joists are oftentimes made from 16-gauge steel, which tends to be more difficult to drill or perforate. Furthermore, additional elements are oftentimes difficult to attach to light gauge steel C-profile joists.
Trichord open web joists are generally more rigid than light gauge steel with C-profile but often have to be custom manufactured to fit span, load, etc. A further common disadvantage of trichord open web joists is that they are difficult to attach or to join with hangers.
Screw fabricated steel truss joists often suffer from 4 common drawbacks: They are labor-intensive, expensive in manufacturing, have to be custom made and tend to loosening of screws leading to impaired stability and additional wear.
Thus, there is still a need for improved weight bearing elements and methods to produce improved weight bearing elements.